The present invention relates to a process for the production of foundry molds and cores from foundry sand mixed with a binder, in which process a reagent is supplied with the aid of a carrier airflow to the sand mixed with a binder located in a casing, and as a result of which the sand is hardened to form a dimensionally stable or rigid mold or core.
Processes for the production of foundry molds and cores according to the so-called box process are known in numerous different forms. The process essentially comprises mixing the foundry sand with a binder. The thus prepared sand is introduced into a casing constructed as the mold or core. A reagent, e.g. a catalyst in a carrier airflow is then introduced into the casing, so that a reaction takes place between the binder and the reagent, through which the mold is transformed into a dimensionally stable or rigid body. The reagents can be constituted e.g. by catalysts in the form of amines of different types.
In time the process has undergone various improvements and in particular the preheating of the reagent and the carrier air has led to a speeding up of the production of molds and cores. The normally liquid reagent must be converted into a gaseous state, so that there is a uniform hardening of the sand at all points. This is in particular achieved by heating the carrier air and the reagent.
A particular disadvantage of this process is that through the use of amines as reagents it is not possible to avoid considerable odorous annoyance for personnel working in such installations. These amines have different boiling points and correspondingly the odor formation differs. The higher the boiling point of the amine, the lower the odorous annoyance. However, it is disadvantageous in the case of such amines with a higher boiling point that the evaporation does no take place sufficiently rapidly, so that its distribution in the sand can vary, so that the mold or core has a lower quality.